Hot beverages, normally coffee, tea or the like, are frequently sold as a takeout item and supplied in disposable cups with thin plastic lids. Such lids are generally of two types, lids which are to be removed in their entirety for access to the contents of the cup, and lids which utilize a fold-back or tear-back flap to expose a large drinking opening.
If the lid is to be removed in its entirety when consuming the contents of the cup, the lid will frequently include a sipping opening which allows the consumer to cautiously sip the beverage until such time as the coffee has sufficiently cooled to allow for a direct drinking thereof from the cup. In those lids wherein a closure flap is provided, the opening formed upon removal of the flap must be quite substantial to allow for a drinking of the coffee in a normal and rather high flow manner. Sipping through such an opening, particularly when the beverage is very hot, can be troublesome.
As consumer preferences in lids will vary, a supplier of the dispensed beverage will frequently have to stock both types of lids to meet customer requirements.
Patents of general interest with regard to the environment of the invention include Lane et al. (U.S. Pat. No. 5,699,927) wherein the lid, in addition to providing an enlarged drinking opening with a closure flap, also includes a small vent opening 74 within a rather deep recess 72 for the venting of steam. Such a steam venting hole would have no sipping capability.
Another such patent is Zettle et al. (U.S. Pat. No. 6,783,019) which, in addition to an enlarged drinking opening or spout 108 through the lid itself, also includes a straw hole 106 with a gasket 200. This hole, because of its structure specifically for the accommodation of a straw, is unlikely to be used to access hot liquids. Further, positioning of the straw opening substantially inward from the edge portion of the lid will preclude any possibility of a cautious sipping of the cup contents therethrough.
The patent to Warden et al. (U.S. Pat. No. 5,398,843) discloses a breakout section which is pushed inward to provide a drinking opening. This patent also discloses a highly restricted vent opening which is probably necessary to facilitate flow of fluid through the rather restricted drinking opening, and clearly is not intended to, and could not, as constructed, permit a sipping therethrough.
The invention has several advantages over the prior art cup lids employing a tear-back flap to expose the drinking opening and mechanisms to retain the flap in an open position for drinking the contents of the cup. It is known in the art that heat from contents of a cup can soften or distort the thermoplastic material of the cup lid, which interferes with the mechanism by which the flap is locked into place after the drinking opening is exposed. The embodiments of the invention overcome this since the sealing lug (FIGS. 1 to 4) and projecting lugs (FIGS. 5 to 9) are located on a tab that is beyond the outer periphery of the lid and thus remote from the heat of the contents of the cup.
Further, the location of the sealing lug or projecting lugs on the tab that is external to the lid rim means that the contents of the cup do not come into contact with the underside of the tab. This is an important improvement over the prior art cup lids because it ensures that the drinker's fingers will not come into contact with the cup's contents as the drinker tears back the flap and presses down on the area directly beneath the tab to engage the flap in an open position on the lid. Such is not the case in prior art cup lids where the lugs or locking protrusions used to secure the flap in an open position are located inside the outer periphery of the lid and thus exposed to the contents of the cup.